I'll hopefully be getting a new motherboard (Gigabyte P35 DS3L Maybe...)+ E2160 CPU and I'm hoping to overclock to at least 3.2Ghz, but I'm using 2GB of PC5300 667Mhz 1.8V Ram and i'm wondering if that would limit the overclock?

I would get some 6400's. It is hard not to with the prices so low these days. It would also give you the option to OC the RAM (with a divider) and/or tighten up the timings. I like to have a little breathing room in my hardware. (just don't look at my PSU, lol)

Yes, it does, I had to drop my fsb back to 266 because my DDR2 667 isn't stable at 740mhz (3:2 linked), only at 700mhz and I don't want to start messing with unlinked.

Also, at least on my motherboard, 1:1 linked sets it to the QDR frequency, not the FSB, so if I were to run at 2.66GHz at 1:1 ratio my memory would actually be running at DDR2 1066 instead of DDR2 533.

I'll hopefully be getting a new motherboard (Gigabyte P35 DS3L Maybe...)+ E2160 CPU and I'm hoping to overclock to at least 3.2Ghz, but I'm using 2GB of PC5300 667Mhz 1.8V Ram and i'm wondering if that would limit the overclock?

No, your ram wouldn't limit your overclock. You are not forced to overclock synchronously. If you have crappy ram, simply choose asynchronous settings and go for it.